Tracking S‐Scheme Charge Transfer Pathways in Mo2C/CdS H2‐Evolution Photocatalysts

Developing efficient and low‐cost photocatalysts and deep investigations on the charge separation and transfer pathways are still two key challenges in achieving practical photocatalytic application. Herein, the NiS‐modified Mo 2 C/CdS layered nanojunction with cascade 2D coupling interfaces for efficient photocatalytic H 2 evolution is constructed. The as‐prepared ternary step‐scheme (S‐scheme) photocatalysts show excellent photocatalytic hydrogen‐evolution performance of 24.03 mmol g −1 h −1 , which is 7.83 and 3.83 times higher than that of CdS and CdS/NiS. Surprisingly, it is found that Mo 2 C can serve as a semiconductor in photocatalytic hydrogen evolution, instead of as a cocatalyst. The charge transfer pathways from Mo 2 C to CdS are identified via both, in situ irradiation X‐ray photoelectron spectroscopy (XPS) (ISI XPS) and ultraviolet photoelectron spectroscopy (UPS). Notably, this is the first report using Mo 2 C as a semiconductor for photocatalytic application, which gives full play to the advantages of light‐harvesting and charges separation.